Multi-speed transmission having three planetary gear sets

ABSTRACT

A transmission is provided having an input member, an output member, three planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices include clutches and brakes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 12/355,440filed on Jan. 16, 2009. The disclosure of the above application isincorporated herein by reference.

FIELD

The invention relates generally to a multiple speed transmission havinga plurality of planetary gear sets and a plurality of torquetransmitting devices, and more particularly to a transmission havingseven speeds, three planetary gear sets and a plurality of torquetransmitting devices.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A typical multiple speed transmission uses a combination of frictionclutches, planetary gear arrangements and fixed interconnections toachieve a plurality of gear ratios. The number and physical arrangementof the planetary gear sets, generally, are dictated by packaging, costand desired speed ratios.

While current transmissions achieve their intended purpose, the need fornew and improved transmission configurations which exhibit improvedperformance, especially from the standpoints of efficiency,responsiveness and smoothness and improved packaging, primarily reducedsize and weight, is essentially constant. Accordingly, there is a needfor an improved, cost-effective, compact multiple speed transmission.

SUMMARY

A transmission is provided having an input member, an output member,three planetary gear sets, a plurality of interconnecting members and aplurality of torque transmitting devices. Each of the planetary gearsets includes first, second and third members. The torque transmittingdevices are for example clutches and brakes.

In one embodiment of the transmission, the input member is continuouslyinterconnected to the sun gear member of the second planetary gear setand the output member is continuously interconnected to the ring gearmember of the first planetary gear set and the carrier member of thesecond planetary gear set.

Further, a first interconnecting member continuously interconnects thesun gear member of the first planetary gear set to a stationary member.A second interconnecting member continuously interconnects the carriermember of the first planetary gear set with the ring gear member of thethird planetary gear set.

Additionally, a first torque transmitting mechanism is selectivelyengageable to interconnect at least one of the sun gear member of thesecond planetary gear set and the input member with the sun gear memberof the third planetary gear set. A second torque transmitting mechanismis selectively engageable to interconnect the sun gear member of thethird planetary gear set with the carrier member of the third planetarygear set. A third torque transmitting mechanism is selectivelyengageable to interconnect at least one of the input member and the sungear member of the second planetary gear set with the carrier member ofthe third planetary gear set. A fourth torque transmitting mechanism isselectively engageable to interconnect the ring gear member of thesecond planetary gear set with the carrier member of the third planetarygear set. A fifth torque transmitting mechanism is selectivelyengageable to interconnect the sun gear member of the third planetarygear set with the stationary member. A sixth torque transmittingmechanism is selectively engageable to interconnect the carrier memberof the third planetary gear set with the stationary member.

The torque transmitting mechanisms are selectively engageable incombinations of at least two to establish at least seven forward speedratios and at least one reverse speed ratio between the input member andthe output member.

In another embodiment of the transmission, the input member iscontinuously interconnected to the sun gear member of the secondplanetary gear set and the output member is continuously interconnectedto the carrier member of the second planetary gear set.

Further, a first interconnecting member continuously interconnects thesun gear member of the first planetary gear set to a stationary member.A second interconnecting member continuously interconnects the ring gearmember of the first planetary gear set with the ring gear member of thesecond planetary gear set. A third interconnecting member continuouslyinterconnects the carrier member of the first planetary gear set withthe ring gear member of the third planetary gear set.

Additionally, a first torque transmitting mechanism is selectivelyengageable to interconnect at least one of the sun gear member of thesecond planetary gear set and the input member with the sun gear memberof the third planetary gear set. A second torque transmitting mechanismis selectively engageable to interconnect at least one of the sun gearmember of the second planetary gear set and the input member with thecarrier member of the third planetary gear set. A third torquetransmitting mechanism is selectively engageable to interconnect atleast one of the ring gear member of the first planetary gear set andthe ring gear member of the second planetary gear set with the carriermember of the third planetary gear set. A fourth torque transmittingmechanism is selectively engageable to interconnect the carrier memberof the second planetary gear set with the sun member of the thirdplanetary gear set. A fifth torque transmitting mechanism is selectivelyengageable to interconnect the carrier member of the third planetarygear set with the stationary member.

Moreover, the torque transmitting mechanisms are selectively engageablein combinations of at least two to establish at least seven forwardspeed ratios and at least one reverse speed ratio between the inputmember and the output member

Thus, it is an aspect of the present invention to provide a transmissionhaving at least seven forward speeds and at least one reverse.

Further aspects and advantages of the present invention will becomeapparent by reference to the following description and appended drawingswherein like reference numbers refer to the same component, element orfeature.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a lever diagram of an embodiment of a seven speed transmissionaccording to the present invention;

FIG. 2 is a diagrammatic view of an embodiment of a seven speedtransmission according to the present invention;

FIG. 3 is a truth table presenting the state of engagement of thevarious torque transmitting mechanisms in each of the available forwardand reverse speeds or gear ratios of the transmission illustrated inFIGS. 1 and 2;

FIG. 4 is a lever diagram of another embodiment of a seven speedtransmission according to the present invention;

FIG. 5 is a diagrammatic view of another embodiment of a seven speedtransmission according to the present invention; and

FIG. 6 is a truth table presenting the state of engagement of thevarious torque transmitting mechanisms in each of the available forwardand reverse speeds or gear ratios of the transmission illustrated inFIGS. 4 and 5.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

Referring now to FIG. 1, an embodiment of an seven speed transmission 10is illustrated in a lever diagram format. A lever diagram is a schematicrepresentation of the components of a mechanical device such as anautomatic transmission. Each individual lever represents a planetarygear set wherein the three basic mechanical components of the planetarygear are each represented by a node. Therefore, a single lever containsthree nodes: one for the sun gear, one for the planet gear carrier, andone for the ring gear. The relative length between the nodes of eachlever can be used to represent the ring-to-sun ratio of each respectivegear set. These lever ratios, in turn, are used to vary the gear ratiosof the transmission in order to achieve an appropriate ratios and ratioprogression. Mechanical couplings or interconnections between the nodesof the various planetary gear sets are illustrated by thin, horizontallines and torque transmitting devices such as clutches and brakes arepresented as interleaved fingers. Further explanation of the format,purpose and use of lever diagrams can be found in SAE Paper 810102, “TheLever Analogy: A New Tool in Transmission Analysis” by Benford andLeising which is hereby fully incorporated by reference.

The transmission 10 includes an input shaft or member 12, a firstplanetary gear set 14 having three nodes: a first node 14A, a secondnode 14B and a third node 14C, a second planetary gear set 16 havingthree nodes: a first node 16A, a second node 16B and a third node 16C, athird planetary gear set 18 having three nodes: a first node 18A, asecond node 18B and a third node 18C, and an output shaft or member 20.

The input shaft or member 12 is coupled to the first node 16A of thesecond planetary gear set 16. The output shaft or member 20 is coupledto the first node 14A of the first planetary gear set 14 and second node16B of the second planetary gear set 16. The first node 14B of the firstplanetary gear set 14 is coupled to the third node 18C of the thirdplanetary gear set 18. The third node 14C of the first planetary gearset 14 is coupled to ground or the transmission housing.

A first clutch 26 selectively connects the input shaft or member 12 andthe first node 16A of the second planetary gear set 16 with the firstnode 18A of the third planetary gear set 18. A second clutch 28selectively connects the second node 18B of the third planetary gear set18 with the first node 18A of the third planetary gear set 18. A thirdclutch 30 selectively connects the input shaft or member 12 and thefirst node 16A of the second planetary gear set 16 with the second node18B of the third planetary gear set 18. A fourth clutch 32 selectivelyconnects the third node 16C of the second planetary gear set 16 with thesecond node 18B of the third planetary gear set 18. A first brake 34selectively connects the first node 18A of the third planetary gear set18 with a ground, a stationary member, or a transmission housing 50. Asecond brake 36 selectively connects the second node 18B of the thirdplanetary gear set 18 with the ground, the stationary member, or thetransmission housing 50.

Referring now to FIG. 2, a stick diagram presents a schematic layout ofthe embodiment of the seven speed transmission 10 according to thepresent invention. In FIG. 2, the numbering from the lever diagram ofFIG. 1 is carried over. The clutches, brakes, and couplings arecorrespondingly presented whereas the nodes of the planetary gear setsnow appear as components of planetary gear sets such as sun gears, ringgears, planet gears and planet gear carriers.

For example, the planetary gear set 14 includes a sun gear member 14C, aring gear member 14A and a planet gear carrier member 14B that rotatablysupports a set of planet gears 14D (only one of which is shown). The sungear member 14C is connected to a first shaft or interconnecting member42 that is connected to the transmission housing 50, thus restrictingthe rotation of sun gear member 14C. The ring gear member 14A isconnected for common rotation with output shaft 20. The planet carriermember 14B is connected for common rotation with a second shaft orinterconnecting member 44. The planet gears 14D each are configured tointermesh with both the sun gear member 14C and the ring gear member14A.

The planetary gear set 16 includes a sun gear member 16A, a ring gearmember 16C and a planet gear carrier member 16B that rotatably supportsa set of planet gears 16D (only one of which is shown). The sun gearmember 16A is connected for common rotation with input shaft or member12. The ring gear member 16C is connected for common rotation with athird shaft or interconnecting member 46. The planet carrier member 16Bis connected for common rotation with output shaft or member 20. Each ofthe planet gears 16D are configured to intermesh with both the sun gearmember 16A and the ring gear member 16C.

The planetary gear set 18 includes a sun gear member 18A, a ring gearmember 18C and a planet gear carrier member 18B that rotatably supportsa set of planet gears 18D (only one of which is shown). The sun gearmember 18A is connected for common rotation with a fourth shaft orinterconnecting member 48 and with a fifth shaft or interconnectingmember 52. The ring gear member 18C is connected for common rotationwith the second shaft or interconnecting member 44. The planet carriermember 18B is connected for common rotation with the sixth shaft orinterconnecting member 54 and a seventh shaft or interconnecting member56. The planet gears 18D are each configured to intermesh with both thesun gear member 18A and the ring gear member 18C.

The input shaft or member 12 is continuously connected to an engine (notshown) or to a turbine of a torque converter (not shown). The outputshaft or member 20 is continuously connected with the final drive unitor transfer case (not shown).

The torque-transmitting mechanisms or clutches 26, 28, 30, 32 and brakes34 and 36 allow for selective interconnection of the shafts orinterconnecting members, members of the planetary gear sets and thehousing. For example, the first clutch 26 is selectively engageable toconnect the fourth shaft or interconnecting member 48 with the inputshaft or member 12. The second clutch 28 is selectively engageable toconnect the fifth shaft or interconnecting member 52 with the seventhshaft or interconnecting member 56. The third clutch 30 is selectivelyengageable to connect the input shaft or member 12 with the sixth shaftor interconnecting member 54. The fourth clutch 32 is selectivelyengageable to connect the third shaft or interconnecting member 46 withthe sixth shaft or interconnecting member 54. The first brake 34 isselectively engageable to connect the fifth shaft or interconnectingmember 52 with the stationary member or the transmission housing 50 inorder to restrict the fifth interconnecting member 52 from rotatingrelative to the transmission housing 50. The second brake 36 isselectively engageable to connect the seventh shaft or interconnectingmember 56 with the stationary member or the transmission housing 50 inorder to restrict the seventh interconnecting member 56 from rotatingrelative to the transmission housing 50.

Referring now to FIG. 2 and FIG. 3, the operation of the embodiment ofthe seven speed transmission 10 will be described. It will beappreciated that transmission 10 is capable of transmitting torque fromthe input shaft or member 12 to the output shaft or member 20 in atleast seven forward speed or torque ratios and at least one reversespeed or torque ratio with single transition sequential shifts and adouble overdrive. Each forward and reverse speed or torque ratio isattained by engagement of one or more of the torque-transmittingmechanisms (i.e. first clutch 26, second clutch 28, third clutch 30,fourth clutch 32, first brake 34 and second brake 36), as will beexplained below. FIG. 3 is a truth table presenting the variouscombinations of torque-transmitting mechanisms that are activated orengaged to achieve the various gear states. An “X” in the box means thatthe particular clutch or brake is engaged to achieve the desired gearstate. An “O” represents that the particular torque transmitting device(i.e. a brake or clutch) is on or active, but not carrying torque.Actual numerical gear ratios of the various gear states are alsopresented although it should be appreciated that these numerical valuesare exemplary only and that they may be adjusted over significant rangesto accommodate various applications and operational criteria of thetransmission 10. An example of the gear ratios that may be obtainedusing the embodiments of the present invention are also shown in FIG. 3.Of course, other gear ratios are achievable depending on the geardiameter, gear teeth count and gear configuration selected.

To establish a reverse gear first clutch 26 and second brake 36 areengaged or activated. The first clutch 26 connects the fourth shaft orinterconnecting member 48 with the input shaft or member 12. The secondbrake 36 connects the seventh shaft or interconnecting member 56 withthe stationary member or the transmission housing 50 in order torestrict the seventh interconnecting member 56 from rotating relative tothe transmission housing 50. Likewise, the seven forward ratios areachieved through different combinations of clutch and brake engagement,as shown in FIG. 3.

It will be appreciated that the foregoing explanation of operation andgear states of the seven speed transmission 10 assumes, first of all,that all the clutches or brakes not specifically referenced in a givengear state are inactive or disengaged and, second of all, that duringgear shifts, i.e., changes of gear state, between at least adjacent gearstates, a clutch or brake engaged or activated in both gear states willremain engaged or activated.

Referring now to FIG. 4, another embodiment of a seven speedtransmission 100 is illustrated in a lever diagram format. Thetransmission 100 includes an input shaft or member 112, a firstplanetary gear set 114 having three nodes: a first node 114A, a secondnode 114B and a third node 114C, a second planetary gear set 116 havingthree nodes: a first node 116A, a second node 116B and a third node116C, a third planetary gear set 118 having three nodes: a first node118A, a second node 118B and a third node 118C, and an output shaft ormember 120.

The input shaft or member 112 is coupled to the first node 116A of thesecond planetary gear set 116. The output shaft or member 120 is coupledto the second node 116B of the second planetary gear set 116. The thirdnode 114C of the first planetary gear set 114 is coupled to the thirdnode 116C of the second planetary gear set 116. The third node 118C ofthe third planetary gear set 118 is coupled to the second node 114B ofthe first planetary gear set 114. The first node 114A of the firstplanetary gear set 114 is permanently connected to ground ortransmission housing 150.

A first clutch 126 selectively connects the input shaft or member 112and the first node 116A of the second planetary gear set 116 with thefirst node 118A of the third planetary gear set 118. A second clutch 128selectively connects the input shaft or member 112 and the first node116A of the second planetary gear set 116 with the second node 1188 ofthe third planetary gear set 118. A third clutch 130 selectivelyconnects the second node 118B of the third planetary gear set 118 withthe third node 114C of the first planetary gear set 114 and the thirdnode 116C of the second planetary gear set 116. A fourth clutch 132selectively connects the second node 116B of the second planetary gearset 116 and the output shaft 120 with the first node 118A of the thirdplanetary gear set 118. A brake 134 selectively connects the second node1188 of the third planetary gear set 118 with a ground, a stationarymember, or a transmission housing 150.

Referring now to FIG. 5, a stick diagram presents a schematic layout ofthe embodiment of the seven speed transmission 100 according to thepresent invention. In FIG. 5, the numbering from the lever diagram ofFIG. 4 is carried over. The clutches, brake and couplings arecorrespondingly presented whereas the nodes of the planetary gear setsnow appear as components of planetary gear sets such as sun gears, ringgears, planet gears and planet gear carriers.

For example, the planetary gear set 114 includes a sun gear member 114A,a ring gear member 114C and a planet gear carrier member 114B thatrotatably supports a set of planet gears 114D (only one of which isshown). The sun gear member 114A is connected to a first shaft orinterconnecting member 142 that is permanently connected to ground ortransmission housing 150 and, thus, restricts the rotation of firstshaft or interconnecting member 142. The ring gear member 114C isconnected for common rotation with a second shaft or interconnectingmember 144. The planet carrier member 114B is connected for commonrotation with a third shaft or interconnecting member 146. The planetgears 114D are each configured to intermesh with both the sun gearmember 114A and the ring gear member 114C.

The planetary gear set 116 includes a sun gear member 116A, a ring gearmember 116C and a planet gear carrier member 116B that rotatablysupports a set of planet gears 116D (only one of which is shown). Thesun gear member 116A is connected for common rotation with input shaftor member 112. The ring gear member 116C is connected for commonrotation with the second shaft or interconnecting member 144. The planetcarrier member 1168 is connected for common rotation with a fourth shaftor interconnecting member 148 and with output shaft or member 120. Theplanet gears 116D each are configured to intermesh with both the sungear member 116A and the ring gear member 116C.

The planetary gear set 118 includes a sun gear member 118A, a ring gearmember 118C and a planet gear carrier member 118B that rotatablysupports a set of planet gears 118D (only one of which is shown). Thesun gear member 118A is connected for common rotation with a fifth shaftor interconnecting member 152 and with a sixth shaft or interconnectingmember 154. The ring gear member 118C is connected for common rotationwith the third shaft or interconnecting member 146. The planet carriermember 118B is connected for common rotation with a seventh shaft orinterconnecting member 156 and with an eighth shaft or interconnectingmember 158. The planet gears 118D are configured to each intermesh withboth the sun gear member 118A and the ring gear member 118C.

The input shaft or member 112 is continuously connected to an engine(not shown) or to a turbine of a torque converter (not shown). Theoutput shaft or member 120 is continuously connected with the finaldrive unit or transfer case (not shown).

The torque-transmitting mechanisms or clutches 126, 128, 130, 132 andbrake 134 allow for selective interconnection of the shafts orinterconnecting members, members of the planetary gear sets and thehousing. For example, the first clutch 126 is selectively engageable toconnect the fifth shaft or interconnecting member 152 with the inputshaft or member 112. The second clutch 128 is selectively engageable toconnect the input shaft or member 112 with the seventh shaft orinterconnecting member 156. The third clutch 130 is selectivelyengageable to connect the second shaft or interconnecting member 144with the seventh shaft or interconnecting member 158. The fourth clutch132 is selectively engageable to connect the fourth shaft orinterconnecting member 148 with the sixth shaft or interconnectingmember 154. The brake 134 is selectively engageable to connect theseventh shaft or interconnecting member 156 with the stationary memberor the transmission housing 150 in order to restrict the member 156 fromrotating relative to the transmission housing 150.

Referring now to FIG. 5 and FIG. 6, the operation of the embodiment ofthe seven speed transmission 100 will be described. It will beappreciated that transmission 100 is capable of transmitting torque fromthe input shaft or member 112 to the output shaft or member 120 in atleast seven forward speed or torque ratios and at least one reversespeed or torque ratio with single transition sequential shifts and adouble overdrive. Each forward and reverse speed or torque ratio isattained by engagement of one or more of the torque-transmittingmechanisms (i.e. first clutch 126, second clutch 128, third clutch 130,fourth clutch 132 and brake 134), as will be explained below. FIG. 6 isa truth table presenting the various combinations of torque-transmittingmechanisms that are activated or engaged to achieve the various gearstates. An “X” in the box means that the particular clutch or brake isengaged to achieve the desired gear state. An “O” represents that theparticular torque transmitting device (i.e. a brake or clutch) is on oractive, but not carrying torque. Actual numerical gear ratios of thevarious gear states are also presented although it should be appreciatedthat these numerical values are exemplary only and that they may beadjusted over significant ranges to accommodate various applications andoperational criteria of the transmission 100. An example of the gearratios that may be obtained using the embodiments of the presentinvention are also shown in FIG. 6. Of course, other gear ratios areachievable depending on the gear diameter, gear teeth count and gearconfiguration selected.

To establish a reverse gear, the first clutch 126 and brake 134 areengaged or activated. The first clutch 126 connects the fifth shaft orinterconnecting member 152 with the input shaft or member 112. The brake134 connects the seventh shaft or interconnecting member 156 with thestationary member or the transmission housing 150 in order to restrictthe member 156 from rotating relative to the transmission housing 150.Likewise, the seven forward ratios are achieved through differentcombinations of clutch and brake engagement, as shown in FIG. 6.

It will be appreciated that the foregoing explanation of operation andgear states of the seven speed transmission 100 assumes, first of all,that all the clutches or brakes not specifically referenced in a givengear state are inactive or disengaged and, second of all, that duringgear shifts, i.e., changes of gear state, between at least adjacent gearstates, a clutch or brake engaged or activated in both gear states willremain engaged or activated.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A transmission comprising: an input member; an output member; first,second, and third planetary gear sets each having first, second andthird members; a first interconnecting member continuouslyinterconnecting the first member of the first planetary gear set to astationary member; a second interconnecting member continuouslyinterconnecting the third member of the first planetary gear set withthe third member of the second planetary gear set; a thirdinterconnecting member continuously interconnecting the second member ofthe first planetary gear set with the third member of the thirdplanetary gear set; and five torque transmitting mechanisms eachselectively engageable to interconnect at least one of the first,second, and third members with at least one other of the first, second,third members and the stationary member, and wherein the torquetransmitting mechanisms are selectively engageable in combinations of atleast two to establish at least seven forward speed ratios and at leastone reverse speed ratio between the input member and the output member.2. The transmission of claim 1 wherein a first of the five torquetransmitting mechanisms is selectively engageable to interconnect atleast one of the first member of the second planetary gear set and theinput member with the first member of the third planetary gear set. 3.The transmission of claim 2 wherein a second of the five torquetransmitting mechanisms is selectively engageable to interconnect atleast one of the first member of the second planetary gear set and theinput member with the second member of the third planetary gear set. 4.The transmission of claim 3 wherein a third of the five torquetransmitting mechanisms is selectively engageable to interconnect atleast one of the third member of the first planetary gear set and thethird member of the second planetary gear set with the second member ofthe third planetary gear set.
 5. The transmission of claim 4 wherein afourth of the five torque transmitting mechanisms is selectivelyengageable to interconnect the second member of the second planetarygear set with the first member of the third planetary gear set.
 6. Thetransmission of claim 5 wherein a fifth of the five torque transmittingmechanisms is selectively engageable to interconnect the second memberof the third planetary gear set with the stationary member.
 7. Thetransmission of claim 6 wherein the first members of the first, secondand third planetary gear sets are sun gears, the second members of thefirst, second and third planetary gear sets are carrier members, and thethird members of the first, second and third planetary gear sets arering gears.
 8. The transmission of claim 1 wherein one of the torquetransmitting mechanisms is a brake for connecting at least one of thefirst, second, and third members to the stationary member and four ofthe torque transmitting mechanisms are clutches for connecting a set ofthe first, second, and third members to another set of the first,second, and third members.
 9. The transmission of claim 1 wherein theinput member is continuously interconnected with the first member of thesecond planetary gear set.
 10. The transmission of claim 1 wherein theoutput member is continuously interconnected with the second member ofthe second planetary gear set.
 11. The transmission of claim 1 whereinthe stationary member is a transmission housing.
 12. A transmissioncomprising: an input member; an output member; first, second, and thirdplanetary gear sets each having first, second and third members, whereinthe input member is continuously interconnected to the first member ofthe second planetary gear set and the output member is continuouslyinterconnected to the second member of the second planetary gear set; afirst interconnecting member continuously interconnecting the firstmember of the first planetary gear set to a stationary member; a secondinterconnecting member continuously interconnecting the third member ofthe first planetary gear set with the third member of the secondplanetary gear set; a third interconnecting member continuouslyinterconnecting the second member of the first planetary gear set withthe third member of the third planetary gear set; and a first torquetransmitting mechanism selectively engageable to interconnect at leastone of the first member of the second planetary gear set and the inputmember with the first member of the third planetary gear set; a secondtorque transmitting mechanism selectively engageable to interconnect atleast one of the first member of the second planetary gear set and theinput member with the second member of the third planetary gear set; athird torque transmitting mechanism selectively engageable tointerconnect at least one of the third member of the first planetarygear set and the third member of the second planetary gear set with thesecond member of the third planetary gear set; a fourth torquetransmitting mechanism selectively engageable to interconnect the secondmember of the second planetary gear set with the first member of thethird planetary gear set; and a fifth torque transmitting mechanismselectively engageable to interconnect the second member of the thirdplanetary gear set with the stationary member, and wherein the torquetransmitting mechanisms are selectively engageable in combinations of atleast two to establish at least seven forward speed ratios and at leastone reverse speed ratio between the input member and the output member.13. The transmission of claim 12 wherein the first members of the first,second and third planetary gear sets are sun gears, the second membersof the first, second and third planetary gear sets are carrier members,and the third members of the first, second and third planetary gear setsare ring gears.
 14. The transmission of claim 12 wherein the stationarymember is a transmission housing.
 15. A transmission comprising: aninput member; an output member; first, second, and third planetary gearsets each having a sun gear, a carrier member, and a ring gear; a firstinterconnecting member continuously interconnecting the sun gear of thefirst planetary gear set to a stationary member; a secondinterconnecting member continuously interconnecting the ring gear of thefirst planetary gear set with the ring gear of the second planetary gearset; a third interconnecting member continuously interconnecting thecarrier member of the first planetary gear set with the ring gear of thethird planetary gear set; and a first torque transmitting mechanismselectively engageable to interconnect at least one of the sun gear ofthe second planetary gear set and the input member with the sun gear ofthe third planetary gear set; a second torque transmitting mechanismselectively engageable to interconnect at least one of the sun gear ofthe second planetary gear set and the input member with the carriermember of the third planetary gear set; a third torque transmittingmechanism selectively engageable to interconnect at least one of thering gear of the first planetary gear set and the ring gear of thesecond planetary gear set with the carrier member of the third planetarygear set; a fourth torque transmitting mechanism selectively engageableto interconnect the carrier member of the second planetary gear set withthe sun gear of the third planetary gear set; and a fifth torquetransmitting mechanism selectively engageable to interconnect thecarrier member of the third planetary gear set with the stationarymember, and wherein the torque transmitting mechanisms are selectivelyengageable in combinations of at least two to establish at least sevenforward speed ratios and at least one reverse speed ratio between theinput member and the output member.
 16. The transmission of claim 15wherein the input member is continuously interconnected to the sun gearof the second planetary gear set and the output member is continuouslyinterconnected to the carrier member of the second planetary gear set.17. The transmission of claim 15 wherein the stationary member is atransmission housing.